Eyes

Question 1

Cornea vs pupil vs iris vs lens vs retina

Answer 1

protective layer that gathers and focus light vs absorbs light, regulates amount of light coming in vs adjust pupil size vs refracts and focuses light vs turns light into signals for brain, DOES NOT REFRACT OR FOCUS

Question 2

Anterior chamber vs posterior chamber vs vitreous

Answer 2

lies in front of iris vs in b/w iris and lens vs behind lens that supports retina

Question 3

Ciliary body vs canal of Sclemm vs ciliary muscle

Answer 3

produces aquaeous humor vs drains aq humor vs changes lens size

Question 4

Describe the visual pathway

Answer 4

Cornea —> pupil —> anterior chamber —> iris —> posterior chamber —> lens —> retina –> optic nerves –> optic chiasm (where optic nerves cross & meet) –> optic tracts –> lateral geniculate nucleus –> temporal and parietal lobes –> visual cortex in occipital lobe. Basically everything in left visual field = processed by right side of brain and everything in right visual field = process by left side of brain

Question 5

What is parallel processing? What’s parvo and magno pathway?

Answer 5

ability to simultaneously process color, shape and motion. Parvo - high spatial resolution and low temporal resolution –> detects shape of stationary things, can detect color; magno - high temporal resolution, low spatial resolution –> detects motion, can’t detect color

Question 6

Where are retinal blood vessels vs choroid blood vessels?

Answer 6

in retina vs b/w sclera and retina

Question 7

Phototransduction cascade

Answer 7

light hits 11-cis-retinal in rhodopsin in rod => all trans retinal –> rhodopsin changes shape –> alpha subunit of transducin binds to PDE –> turns cyclic GMP to GMP —> inc GMP closes Na channels –> hyperpolarization of cell –> rod turns off –> bipolar cell turns on

Question 8

Constrictor and dilator pupillae

Answer 8

changes pupil size

Question 9

Does the iris have photoreceptors?

Answer 9

No, only the retina does

Question 10

What is the fovea?

Answer 10

Center of retina containing cones

Question 11

What is it called when a lens is refocusing on an object? Does it thicken or flatten when focusing on a closer or farther object?

Answer 11

Accommodation via suspensory ligaments. Thickens for focusing on closer (ciliary muscles contract), flattens for focusing on farther (ciliary muscles relax)

Question 12

Convergence vs mydriasis vs contrast

Answer 12

When eyes move toward one another to focus on very close up objects vs term for dilation of pupil vs diff in color and brightness

Question 13

Extrinsic vs intrinsic eye muscles

Answer 13

For mechanical movement of eyeball like convergence, saccadic movements, tracking vs movement within the eye

Question 14

What kind of lens do you need to fix myopia?

Answer 14

Concave diverging lens

Question 15

Weber’s Law

Answer 15

Change in a stimulus that will be just noticeable is a constant ratio to orig stimulus

Question 16

Duplexity or duplicity theory of vision

Answer 16

Retina contains 2 types of photoreceptors: rods and cones

Question 17

amacrine and horizontal cells

vs bipolar cells vs ganglion cells

Answer 17

receive input from photoreceptors before passing them to bipolar and ganglion cells (they’re basically interneurons) vs highlight gradients between adjacent rods and cones vs with which bipolar cells synapse to form optic nerve (but bipolar cells don’t make up optic nerve, JUST GANGLION CELLS)

Question 18

Which nervous system causes pupil dilation? How does pupil dilation affect focusing?

Answer 18

Sympathetic. Lets more light in, but harder to focus on closer objects

Question 19

What are 3 types of photoreceptor cells?

Answer 19

rods, cones, and photosensitive retinal ganglion cells - don’t directly communicate visual info to brain, they’re involved in pupillary reflex

Question 20

Presbyopia vs amblyopia vs strabismus vs nystagmus

Answer 20

Type of hyperopia (farsightedness), inability to focus vision of close-up objects vs one eye = communicating less visual info than other eye —> loss of vision in that eye —> brain learns to ignore visual stimulation of non dominant eye vs “lazy eye”, lack of coordination b/w extraocular muscles that orient eyes together in same direction, if not corrected —> non dominant eye will lose function, causes amblyopia vs condition of involuntary eye movements like eye shutter, doesn’t affect vision

Question 21

Describe types of monocular cues

Answer 21

interposition - infers position, motion parallax/relative motion - when you’re moving, objects closer than your visual focus pt move opposite direction as you and objects farther from your visual focus pt move in same direction as you (ex: car vs moon), relative size - infers distance: if 2 objects = similar size then the smaller object = perceived farther away, relative height - infers distance: higher objects = perceived further while lower objects = perceived closer